Propulsion system

ABSTRACT

A propulsion system for a vessel is described which includes an intake duct and an annular duct which together define a passage which provides two 180* reversals of direction. The annular duct provides a passage of increasing mean diameter and continuously decreasing interior cross section. An impeller accelerates the water by imposing dynamic and centrifugal forces thereon. Stator blades are provided to cause discharge of the water in a direction essentially straight to the rear of the boat.

United States Patent Rodler, Jr.

3,809,005 May 7, 1974 PROPULSION SYSTEM Waldo E. Rodler, Jr., 1488Cherry Garden Ln., San Jose, Calif. 95125 Filed: July 20, 1972 Appl.No.: 273,503

Inventor:

US. Cl ..115/12 R, 60/221,114/151, 239/265.19, 115/12 A Int. Cl B6 3h25/ 46 Field of Search 115/35, 70, l1, 12, 14; 114/151; 239/265.l9, 11,12; 60/221, 222

References Cited UNITED STATES PATENTS 10/1965 Gongwer 114/151 4/1971Wislicenus et a1 115/12 1l/l966 Gongwer 115/12 Smith 115/12 PrimaryExaminer-Trygve M. Blix Assistant ExaminerDonald W. Underwood Attorney,Agent, or FirmFitch, Even, Tabin &

Luedeka 57] ABSTRACT A propulsion system for a vessel is described whichincludes an intake duct and an annular duct which together define apassage which provides two 180 reversals of direction. The annular ductprovides a passage of increasing mean diameter and continuouslydecreasing interior cross section. An impeller accelerates the water byimposing dynamic and centrifugal forces thereon. Stator blades areprovided to cause discharge of the water in a direction essentiallystraight to the rear of the boat.

7 Claims, 5 Drawing Figures :aLaosLoos PATENTEUIIAY 7 I974 SHEET 1 BF 2PROPULSION SYSTEM This invention relates generally to propulsion systemsand, more particularly, to an improved propulsion system for a vessel.

Many so-called water-jet propulsion systems have been proposed for usein propelling vessels. Such systems have an advantage over the moretraditional rotary propeller type propulsion systems in that they arecapable of operating in shallow water, are safer to nearby swimmers orwater skiers, and are capable of producing higher speeds and quickeracceleration. The so-called water-jet propulsion systems are especiallysuited to small craft, although larger vessels may also employ suchpropulsion systems.

Notwithstanding the foregoing advantages, prior art water-jet propulsionsystems suffer from certain significant drawbacks. Efficient matching ofthe torque and speed requirements of the system to its driving engine isoften difficult. Frequently, such systems suffer from a thrust angleimbalance which requires a massive construction to offset the non-axialcomponent of the thrust. Often, the size of the prior art water-jetpropulsion systems is excessive, occupying space which is needed forother purposes in the vessel. Also, internal losses in many of the priorart systems are considerable, resulting in an inherent lower efficiency.

Accordingly, it is an object of the present invention to provide animproved propulsion system for a vessel.

Another object of the invention is to provide an improved vesselpropulsion system of the so-called waterjet type.

It is another object of the invention to provide a water-jet propulsionsystem for a vessel which is of relatively compact physical size.

A further object of the invention is to provide a water-jet propulsionsystem for a vessel which is low in cost and highly efficient inoperation.

Other objects of the invention will become apparent to those skilled inthe art from the following description, taken in connection with theaccompanying drawings wherein:

FIG. 1 is a side elevational view illustrating a preferred embodiment ofthe invention;

FIG. 2 is a rear view of the embodiment shown in FIG. 1;

FIG. 3 is an enlarged full section side view of the embodiment shown inFIG. 1;

FIG. 4 is a partial sectional view of a portion of FIG. 3, illustratingoperation of thrust reversing means; and

FIG. 5 is an elevational view of a further embodiment of the invention.

Very generally, the propulsion system of the invention comprises meansdefining an intake duct 11 having an intake orifice 12 adapted to bepositioned for receiving water. The intake duct is shaped to directwater flowing into it through a change in direction of substantially180. Means l4 define an annular duct 15 contiguous with the intake ductat the end of the intake duct opposite the intake orifice. The annularduct has a continuously increasing mean diameter and a continuouslydecreasing interior cross section, and is shaped to direct water flowingtherethrough through a change in direction of substantially 180. Movingimpeller blades within the annular duct accelerate the water by means ofdynamic and centrifugal forces, and stator blading in the annular ductis designed to neutralize circumferential swirl in the water produced bythe moving impeller blades. The water is thus discharged in a directionessentially straight to the rear of the vessel.

Referring now more particularly to the drawings, FIGS. l-4 show thepreferred embodiment of the invention as comprising a so-calledinboard/outdrive propulsion system attached to the rear of the vessel13, the vessel being shown in section in FIG. 3. The vessel includes atransom 23 and a keel 25. An opening 27 is provided in the lower part ofthe transom, and a propulsion system mount 29 is fitted within theopening 27 and is secured to the transom by suitable means, not shown,at a flange 33 of the mount. 7

The mount 29 supports a shaft housing 35 in which a rotary drive shaft37 is provided. Suitable means, not shown, are provided at one end ofthe drive shaft 37 for coupling to a suitable driving engine, not shown.The other end of the drive shaft 37 carries a yoke 41 which is joined toanother yoke 43 by a universal coupling 45. The mount 29 also supports abilge pump hose 46, shown only in FIG. 3. A discharge hose 48 isattached to the mount 29 to communicate with the bilge pump hose 46.

The yoke 43 is supported on one end of an impeller shaft 47 which, inturn, is mounted in a housing 49 in suitable bearings 51 and 52 therein.A bellows 55 is provided for sealing the universal coupling, and extendsbetween the shaft housing 35 and the bearing housing 49.

The means 10 defining the intake duct 11 is, in the illustratedembodiment, a horn which defines the intake orifice 12 at one end. Theperiphery of the orifice 12 lies in a plane which is inclined slightlyfrom the horizontal at an angle of about 30 and which therefore orientsthe orifice 12 toward the direction in which the vessel 13 is to travel.Accordingly, as the vessel moves through the water, water enters theintake duct 11 at a corresponding velocity.

A cavitation plate 57 is provided toward the lower end of the horn 10.Also, a pair of interior baffles 58 and 59 are supported transversely inthe duct 11 to eliminate excess swirling and turbulence. The intake horn10 is supported by means of suitable bolts 61, one of which is shown inFIG. 3, from the duct means 14.

A steering mount bracket 65 is secured to the flange 33 on a shim plate66. A steering post 67 is mounted in a bearing 67a in the bracket 65 andsupports a steering yoke 68. The steering yoke 68 has a boss 68a whichreceives the post 67. The boss 68a is secured to the post 67 by a pin69. The upper part of the yoke 68 has a boss 68b axially aligned withthe boss 68a. A post 70 is held in the boss 68b by a pin 70a axiallyaligned with the post 67. Thus, the yoke pivots on the posts 67 and 70.

The means 14 which defines the annular duct 15 is provided with a pairof lugs 71 (see FIG. 1) which extend parallel with each other toward thevessel and which are pivotally mounted by means not shown to oppositesides of the yoke 68. Thus, the means 14 may pivot upwardly on the lugs71. A tilt control rod 72 is secured to the outer end of a tilt bracket73 by means of a pivot coupling 74. The tilt control rod 72 extendsthrough a suitable connection 75 to the interior of the vessel 13 and isoperable to move the tilt bracket 73.

Hence, the entire portion of the propelling system aft of the vessel 13may pivot on the lugs 71 to an upwardly tilted position. This places theperiphery of the inlet orifice 12 in a horizontal plane above the lowerlevel or keel 25 of the vessel. This is the non-operating or storedposition of the propulsion system. In the down position shown in FIGS. 1to 3, a stop pin 76 engages a stop bracket 76a to support the assembly.Other holes 80 are provided to place the pin 76 to adjust the angle oftilt.

As may be seen in FIG. 3, a steering control link 77 extends from asuitable coupler 79 in the transom of the vessel. The steering post 70is mounted in. the coupler 79 in alignment with the steering post 67 andwith the centerof the connection between the yoke 43 and the universalcoupling 45. The sides of the yoke 68 pass on opposite sides of thebellows 5S and link to the steering mount bracket 65. Accordingly, theentire assembly aft of the posts 67 and 70 may be turned with the yoke68 by the link 77 to steer the vessel.

A diffuser cone 82 is positioned at the end of the intake duct 11opposite the intake orifice 12. The cone 82 comprises part of the means14 which define the annular duct 15. A plurality of rotor or impellerblades 84 (see FIG. 3) are mounted in an impeller 89 having an innercone extension 85 and an outer ring 85a, and extend inwardly across theannular duct. The impeller 89 is supported on a spindle 86 extendingaxially of the shaft 47 and joined thereto.

A plurality of stator blades 87 are also provided. The stator blades aremounted in the annular duct 15 on the means 14 which define the annularduct 15. The annular duct 15 is contiguous with the inlet duct 11 in theregion of the diffuser cone 82, that is, the end of the inlet ductopposite the intake orifice 12. The duct 15,

. defined by the one end of the horn 10, the diffuser cone 82 and theimpeller 89, has a continuously increasing mean diameter and acontinuously decreasing interior cross section. The duct is shaped todirect water flowing in it through a change in direction ofsubstantially l80, and from a single flowing stream to one which isannular in shape. By changing the direction of flow of the water by 180,the discharge of the water is toward the rear of the vessel, therebycausing propulsion of the vessel in a forward direction. By increasingthe diameter of the annulus, centrifugal force is employed to acceleratethe water. By decreasing the cross section of the annular duct, a nozzleeffect is created to maximize thrust.

The stator blades 87 are arranged to eliminate the swirl ofcircumferential component of velocity in the water produced by rotationof the impeller blades 84. Alternatively, the stator may be ahead of therotor in which case the stator is designed to provide a circum ferentialcomponent of velocity which will approximately match and offset therotational or circumferential component of velocity imparted to thewater as a result of the rotation of the impeller 89. In either case,the stator blades neutralize the effect of the rotary impeller, and theresultant velocity of the water is substantially straight to the rear ofthe vessel. This provides improved thrust and avoids any unbalancedsituation in the steering of the vessel.

It may be seen in FIG. 3 that a zone exists where the water beingdischarged from the annular orifice of the impeller 89 is directed atthe intake horn 10. The intake horn may be streamlined to minimizelosses as a result of its position. As a further provision, a coolingwater pickup intake (not shown) may be placed to receive the waterdischarged from the annular orifice of the impeller 89 and which wouldnormally strike the intake horn 10. This water may then be conveyedthrough a suitable cooling water pickup conduit, not shown, to theengine, not shown. Accordingly, the need for an engine cooling pump iseliminated and losses as a result of the interference of the intake horn10 are minimized.

In order to reverse the direction of thrust provided by the propulsionsystem of the invention, a thrust reverser is provided comprising anannular final segment 10] (see FIG. 3) of the duct means 14. Asillustrated, the annular segment 101 has a shield 103 of curved crosssection extending outwardly. The annular segment is mounted on aplurality of slide pins 104 distributed circumferentially about the ductmeans 14 so that it may slide axially to the position illustrated inFIG. 4. In the latter position, the shield 103 provides a reversal ofthrust for moving the vessel toward the rear. Each of the slide pins 104extends between the main portion of the duct means 14 at a boss 105therefor to a flange 106 on the horn 10. A slide collar 107 is slidablymounted on each pin 104 and extends from the annular segment 101.

Control over the thrust reverser segment 101 is provided by a linkagearrangement which may be seen in FIG. 1. The segment is connected by apair of brackets 108 to a linkage comprised of arms 109 and 110.Suitable means, not shown, inside the vessel 13 may be operated to causethe linkage 109-110 to move the segment 101 to reverse thrust position.

Although the invention has been shown in connection with anoutboard/inboard configuration, it is clearly adaptable to either anoutboard configuration or an inboard configuration.

An outboard configuration is shown in FIG. 5. The intake duct of theembodiment of FIG. 5 is shown at configured in a manner similar to thatof the intake duct of the previous embodiment. The internal constructionof the apparatus of FIG. 5 is identical to that of the previouslydiscussed embodiment insofar as the intake duct, the impeller, and thestator blading are concerned. Power for the impeller is derived from asuitable engine 131 and the power train includes a suitable drive shaftand bevel gear arrangement, not shown, in a housing 132, to transmittorque to the impeller. An engine mount 133 is provided for mounting theoutboard propulsion unit on the transom 137 of the vessel 139.

The propulsion system of the invention provides a number of significantadvantages. The system protrudes a minimal distance below the bottom ofthe vessel to which it is attached, thereby permitting operation of thevessel in extremely shallow water. No exposed propeller blades existbelow the vessel where they are subject to damage by rocks, logs, etc.,and where they can cause possible injury to swimmers or water skiersnearby. Moreover, because any blading is fully shrouded within theducts, improved efficiency results because of a lessening of propellertip losses. The inherent torque and speed requirements of the propulsionsystem of the invention provide a much better match to the normalperformance characteristics of a typical commercially available outboardengine than prior art systems, thus improving overall performance.Because there is no steering imbalance, improved handling ability forthe vessel is provided, and full reverse thrust may be obtained at anyspeed, permitting fast emergency stopping of the boat. Because of thefolded configuration (ie two 180 turns), the overall size of thepropulsion system is substantially less than that of prior art devices,facilitating transportation and storage. The propulsion system of theinvention is extremely low in cost and is relatively easilymanufactured.

It may therefore be seen that the invention provides an improvedpropulsion system for a vessel which is high in efficiency, low in cost,smaller in size, and superior in operation and handling characteristicsto prior art devices.

Various modifications of the invention in addition to those shown anddescribed herein will become apparent to those skilled in the art fromthe foregoing description and accompanying drawings. Such modificationsare intended to fall within the scope of the appended claims.

What is claimed is:

1. A propulsion system for a vessel, comprising, means defining anintake duct having an intake orifice positioned for receiving water,said means defining said intake duct comprising curved flow directingwalls curved continuously to provide a 180 turn for the water to directthe water flowing in an initial direction to a direction opposite to theinitial direction, means defining an annular duct contiguous with saidintake duct at the end of said intake duct opposite said intake orifice,said means defining said annular duct having walls of continuouslyincreasing mean diameter and a continuously decreasing interior crosssection, and curved continuously to provide a second 180 turn to directwater flowing therethrough through a continuous change in direction ofsubstantially 180 such that the water is flowing in a directionapproximate that of its initial direction at said intake orifice andsubstantially opposite to the direction at which it entered said annularduct, a plurality of stator blades arranged within said annular duct,and a rotary impeller having a plurality of impeller blades arrangedwithin said annular duct, said impeller blades and said stator bladesbeing arranged at angles to impart a substantially axial directionalvelocity to the flowing water leaving said annular duct when saidimpeller is rotated.

2. A propulsion system according to claim 1 wherein said impeller isupstream in said annular duct from said stator bladesand, when rotated,imparts a directional component of velocity to the flowing water whichis circumferential with respect to said annular duct, and wherein saidstator blades are mounted in fixed relation to said annular duct atangles such as to substantially remove said circumferential component ofvelocity.

3. A propulsion system according to claim 1 wherein said means definingsaid annular duct include a diffusion cone having its apex toward theend of said intake duct opposite said intake orifice.

4. A propulsion system according to claim 1 including a thrust reverserand means for selectively positioning said thrust reverser at the outletof said annular duct to produce a reversal in the flow of water issuingfrom said annular duct.

5. A propulsion system according to claim 1 including means forpivotally supporting said system, and means for controlling the pivotedposition of said system with respect to the vessel to steer the vessel.

6. A propulsion system according to claim 5 including drive means forrotating said impeller, and a universal joint coupling said drive meansto said impeller.

7. A propulsion system for a vessel, comprising, means defining anintake duct having an intake orifice positioned for receiving water,said intake duct being shaped to direct water flowing therethroughthrough a continuous change in direction of substantially such that thewater is flowing in a direction opposite to its initial direction, adiffusion cone having its apex toward the end of said intake ductopposite said intake orifice, an impeller defining at least part of anannular duct contiguous with said intake duct adjacent said diffusioncone, said annular duct having a continuously increasing mean diameterand a continuously decreasing interior cross section, said annular ductbeing shaped to direct water flowing therethrough through a continuouschange in direction of substantially 180 such that the water is flowingin a direction approximate that of its initial direction at said intakeorifice, a plurality of impeller blades mounted in fixed relation tosaid impeller within said annular duct, drive means for rotating saidimpeller, and a plurality of stator blades arranged within said annularduct at an angle to remove the circumferential component of velocity inthe flowing water which is produced by rotation of said impeller andthus impart a substantially axial directional veloc-

1. A propulsion system for a vessel, comprising, means defining anintake duct having an intake orifice positioned for receiving water,said means defining said intake duct comprising curved flow directingwalls curved continuously to prOvide a 180* turn for the water to directthe water flowing in an initial direction to a direction opposite to theinitial direction, means defining an annular duct contiguous with saidintake duct at the end of said intake duct opposite said intake orifice,said means defining said annular duct having walls of continuouslyincreasing mean diameter and a continuously decreasing interior crosssection, and curved continuously to provide a second 180* turn to directwater flowing therethrough through a continuous change in direction ofsubstantially 180* such that the water is flowing in a directionapproximate that of its initial direction at said intake orifice andsubstantially opposite to the direction at which it entered said annularduct, a plurality of stator blades arranged within said annular duct,and a rotary impeller having a plurality of impeller blades arrangedwithin said annular duct, said impeller blades and said stator bladesbeing arranged at angles to impart a substantially axial directionalvelocity to the flowing water leaving said annular duct when saidimpeller is rotated.
 2. A propulsion system according to claim 1 whereinsaid impeller is upstream in said annular duct from said stator bladesand, when rotated, imparts a directional component of velocity to theflowing water which is circumferential with respect to said annularduct, and wherein said stator blades are mounted in fixed relation tosaid annular duct at angles such as to substantially remove saidcircumferential component of velocity.
 3. A propulsion system accordingto claim 1 wherein said means defining said annular duct include adiffusion cone having its apex toward the end of said intake ductopposite said intake orifice.
 4. A propulsion system according to claim1 including a thrust reverser and means for selectively positioning saidthrust reverser at the outlet of said annular duct to produce a reversalin the flow of water issuing from said annular duct.
 5. A propulsionsystem according to claim 1 including means for pivotally supportingsaid system, and means for controlling the pivoted position of saidsystem with respect to the vessel to steer the vessel.
 6. A propulsionsystem according to claim 5 including drive means for rotating saidimpeller, and a universal joint coupling said drive means to saidimpeller.
 7. A propulsion system for a vessel, comprising, meansdefining an intake duct having an intake orifice positioned forreceiving water, said intake duct being shaped to direct water flowingtherethrough through a continuous change in direction of substantially180* such that the water is flowing in a direction opposite to itsinitial direction, a diffusion cone having its apex toward the end ofsaid intake duct opposite said intake orifice, an impeller defining atleast part of an annular duct contiguous with said intake duct adjacentsaid diffusion cone, said annular duct having a continuously increasingmean diameter and a continuously decreasing interior cross section, saidannular duct being shaped to direct water flowing therethrough through acontinuous change in direction of substantially 180* such that the wateris flowing in a direction approximate that of its initial direction atsaid intake orifice, a plurality of impeller blades mounted in fixedrelation to said impeller within said annular duct, drive means forrotating said impeller, and a plurality of stator blades arranged withinsaid annular duct at an angle to remove the circumferential component ofvelocity in the flowing water which is produced by rotation of saidimpeller and thus impart a substantially axial directional velocity tothe flowing water.